On the 20th of July, residents of W Va, Virginia, Maryland, and DC opposing Rockwool's planned factory in W Virigina built a mock Rockwool factory inside the Lowes hardware store in Gaithersburg. The mock plant was built from Rockwool's own product and was no more welcome there than the real one is in W Va across from an elementary school.
If it ever goes into operation, the Rockwool plant will burn large amounts of both coal and fracked gas to melt obsidian so it can be spun into a rather resource intensive form of fiberglass (literally "rock wool") insulation. The pollution will place W Va tourism at risk regionwide and contribute to Code Red air quality days as far away as Washington DC. Rockwool is also the main planned customer of the Potomac Pipeline, for which a TransCanada subsidiary is seeking Federal eminent domain to condemn State of MD owned parkland.
Chemical and engineering literature suggests that the use of obsidian as a raw material for making fiberglass requires considerably more energy (thus more coal and gas) than making fiberglass from normal raw materials.
"Fiberglass Manufacturing. The manufacture of glass is carried out in a special furnace at about 1550°C (E-Glass) using finely ground raw materials from carefully ..."
"Obsidian is mostly silicon dioxide (about 70%), with a good bit of aluminium oxide and then about 10-20% various other oxides. Melting point for silicon dioxide is 1,710 °C, and for aluminium oxide 2,072 °C. You're going to need a lot of heat for this."
This raises the question of why Rockwool is using obsidian at all, especially given that the fiberglass they are making is just insulation and not high-strenth glass fiber intended to compete against carbon fiber for making bows, high performance boats, or similar highly stressed composite products.